OFFSET
1,1
COMMENTS
Without the initial 7, this gives primes at which difference pattern X42424Y (X and Y >= 8) occurs in A001223. - Labos Elemer
Subsequence of A022007. - Zak Seidov, Nov 01 2011
From Jean-Christophe Hervé, Sep 27 2014: (Start)
The primes in a sextuple a(n), a(n)+4, a(n)+6, a(n)+10, a(n)+12, a(n)+16 are consecutive since a(n)+2, a(n)+8 and a(n)+14 cannot be prime (multiple of 3).
The prime sextuples starting at a(n) give the highest concentration of primes that can occur on an interval of 17 integers (apart intervals starting at p < 7). It is conjectured that there are infinitely many such sextuples.
For n > 1, the 3 odd integers preceding and the 3 odd integers following the sextuple are not prime: a(n)-2 == a(n)+18 == 0 (mod 5), a(n)-4 == a(n)+20 == 0 (mod 3), a(n)-6 == a(n)+22 == 0 (mod 7) and thus a(n) == 97 (mod 210 = 2*3*5*7). (End)
All terms are congruent to 7 (mod 30). - Zak Seidov, May 07 2017
All terms but the first one are congruent to 97 (mod 210). - M. F. Hasler, Jan 18 2022
LINKS
David A. Corneth, Table of n, a(n) for n = 1..10000 (first 1000 terms from Zak Seidov)
T. Forbes and Norman Luhn, Prime k-tuplets
R. J. Mathar, Table of Prime Gap Constellations
EXAMPLE
n=2: 97, 101, 103, 107, 109, 113 are consecutive primes, while 91, 93, 95 and 115, 117 and 119 are not (cf. 4th comment about the border of composites).
MAPLE
for i from 1 to 2*10^5 do if [ithprime(i+1), ithprime(i+2), ithprime(i+3), ithprime(i+4), ithprime(i+5)] = [ithprime(i)+4, ithprime(i)+6, ithprime(i)+10, ithprime(i)+12, ithprime(i)+16] then print(ithprime(i)); fi; od; # Muniru A Asiru, Sep 03 2017
MATHEMATICA
lst = {}; Do[p = Prime[n]; If[PrimeQ[p+4] && PrimeQ[p+6] && PrimeQ[p+10] && PrimeQ[p+12] && PrimeQ[p+16], AppendTo[lst, p]], {n, 1000000}]; lst
Transpose[Select[Partition[Prime[Range[10^6]], 6, 1], Differences[#]=={4, 2, 4, 2, 4}&]][[1]] (* Harvey P. Dale, Mar 15 2015 *)
PROG
(PARI) p=2; q=3; r=5; s=7; t=11; forprime(u=13, 1e9, if(u-p==16 && p%3==1, print1(p", ")); p=q; q=r; r=s; s=t; t=u) \\ Charles R Greathouse IV, Mar 29 2013
(PARI) {next_A022008(p, L=Vec(p+1, 5), m=210, r=Mod(97, m))=for(i=1, oo, L[i%5+1]+16==(p=nextprime(p+1))&&break; p%m>111 && until(r==p=nextprime((p+8)\/210*210+97), ); L[i%5+1]=p); p-16} \\ M. F. Hasler, Jan 18 2022
(Magma) [p: p in PrimesUpTo(2*10^7) | IsPrime(p+4) and IsPrime(p+6) and IsPrime(p+10)and IsPrime(p+12) and IsPrime(p+16)]; // Vincenzo Librandi, Aug 23 2015
(Perl) use ntheory ":all"; say for sieve_prime_cluster(1, 1e8, 4, 6, 10, 12, 16); # Dana Jacobsen, Sep 30 2015
(GAP)
P:=Filtered([1, 3..2*10^7+1], IsPrime);; I:=[4, 2, 4, 2, 4];;
P1:=List([1..Length(P)-1], i->P[i+1]-P[i]);;
A022008:=List(Positions(List([1..Length(P)-Length(I)], i->[P1[i], P1[i+1], P1[i+2], P1[i+3], P1[i+4]]), I), j->P[j]); # Muniru A Asiru, Sep 03 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved